Aegean Airlines’ monthly passenger count surpassed 1 million for the first time in June 2014, marking a 21% year-on-year increase.
The figures for both years include traffic at newly acquired flag carrier Olympic Air, which operates domestic turboprop flights.
International routes recorded the biggest gains, rising 23% compared with 19% across the domestic network.
The regional bases of Heraklion and Rhodes saw the highest international growth, handling 47% and 39% more passengers respectively.
But Athens was also up 22%, benefiting from 14 new route launches in 2014 following several years of contraction.
Year-to-date passenger figures stood at 4.3 million by the end of June – 16% above the same period in 2013.